There is a growing number of photovoltaic (PV) applications where individual direct current/alternating current (DC/AC) inverters are required for each PV module to effectively harvest maximum solar energy and feed clean AC electricity into the power grid. FIG. 1 is a diagram that illustrates the prior art approach to achieving the requirements of such applications. In this prior art approach, a DC junction box is attached at the back-sheet of the PV module. The junction box accepts the DC voltage from the PV cells, provides the necessary protection, and brings out two DC cables with two DC connectors, one each for a positive voltage and a negative voltage. The DC cables are connected to a micro-inverter to produce an AC voltage at its output which is fed to the AC grid via an AC connector.
For greater clarity, FIG. 2 is provided. FIG. 2 shows the schematic of the DC junction box and how it is connected to the PV panel and the micro-inverter. According to FIG. 2, the PV panel 1 is connected to the DC junction box 2. The DC junction box 2 is connected to the micro-inverter 3, and the micro-inverter 3 is connected to the utility grid 4. The DC junction box 2 usually includes a diode 21, a fuse 22, a circuit breaker 23, and an antiparallel diode 24. The diode 21, the fuse 22, and the circuit breaker 23 are conducting the output current of the PV panel. These components contribute to the overall losses of the power conditioning system. Also, these components increase the cost of the power conditioning systems. Therefore, the main drawbacks of this approach are higher cost and longer installation time.
It should be clear that the arrangement in FIG. 2 has drawbacks. The arrangement in FIG. 1 is, unfortunately, also less than desirable. The cables connecting the microinverter to the junction box are exposed to the elements and, as such, are vulnerable to the ravages of cold, heat, and wind. As well, if repair work is to be done on the PV module or on any of the components of the PV system, these loose cables are susceptible to snagging by repair and maintenance personnel. Also, the presence of both AC and DC connectors and the presence of the junction box itself not only can be confusing but may also complicate the installation of PV systems.
Based on the above, there is therefore a need for systems and methods which avoid or mitigate the shortcomings of the prior art.